BOSTON — Fitting, really, that the milestone bucket made by Celtics captain Paul Pierce here at the TD Garden was on a clutch jumper, a step-back 17-footer from (where else?) the right elbow that gave Boston a 103-101 lead with 59 seconds to play in overtime. That’s the spot from which Pierce has made a living as he has progressed into his 30s, the spot so many defenses have determined not to let Pierce get to in big situations. Yet Pierce always seems to manage to get to that spot anyway, and usually makes the defense pay for its indulgence.

In this case, Pierce’s overtime bucket merely helped the Celtics get to a second overtime, where it was, again, Pierce who carried Boston to an exhausting, 117-115, win over the worn-down Mavericks, who committed an eye-opening 27 turnovers on the night. But that elbow jumper in the first overtime was significant—it marked the 23,000th point of Pierce’s underrated career, moving him up to 25th on the NBA’s all-time scoring list. “You never want to let him get shots off in his sweet spots,” Mavericks forward Shawn Marion said. “But that’s Paul Pierce. You can know what you want to do against him sometimes but he will find a way to do it anyway.’

Pierce picked a fine way to get himself into the record books. On a night in which the Celtics were struggling to make shots, Pierce was 11-for-25, 3-for-8 from the 3-point line, scoring 34 points—a season high for any Celtics player. Twelve of those points came in the two overtime periods, including the clutch 3-pointer he made from the left corner to start the scoring in the second overtime. That shot gave the Celtics a 108-105 lead, one that they would never relinquish. Pierce made five of six free throws in the final overtime to help seal the game.

There are times it’s easy to forget that Pierce is now 35 years old, and part of the reason he ranks 25th in points all-time is that he ranks 21st in age among active players. He is the only 35-year-old in the league to be leading his team in scoring, and with his outburst against the Mavericks, he raised his scoring average to 20.5 points per game. Oh, and he also played 44 minutes, the second time in the last week he has played that many minutes in an overtime game.

Pierce said that, in the heat of the back-and-forth between the Mavs and the Celtics, he wasn’t feeling his minutes or aware of his milestone. “I’m caught into the game,” he said. “When the game is tight, the type of game that was going on tonight I’m really caught up in the game, not really thinking about my minutes. … I think it just comes down to mental toughness. You get an edge out there. You see the score go up, then you see a tie score, then the tendency is to get down, so you just have to really maintain a mental edge and just stay positive and know that you’re going to pull through. These types of long games, these types of marathon games, they can be really draining on you.”

Somehow, though, Pierce seems immune to the physical drains that should be sapping a guy with his veteran status. Part of that is because of his conditioning and competitiveness. Part of it, too, is because of the way he has altered his game to emphasize his stop-and-start ability—he has never been purely about athleticism, has never wowed the average fan with dunks and gimmickry. Pierce is about as straightforward a scorer as there is, and because of that, he has never been the type to garner sneaker commercials or gain much by way of national recognition.

“I know guys in the league respect him as much as they can, because of all he has accomplished,” teammate Jason Terry said. “Paul Pierce is not someone most guys want to defend. Maybe on the outside he isn’t as well known, but players know better.”

Pierce showed why that is on Wednesday night. Players know better than to let him get a look at the basket in a tight game from the right elbow. But, even at age 35, Pierce showed why he is a notch ahead of the rest of his contemporaries—he found a way to get the shot off anyway. And he made it.